According to wikipedia it appears there were 1460 employees at the end of 2021 and that appears to be the commitment [1]. The Buffalo News recently published 1619 as the current #, above the threshold. [2]

This might actually mean the chances of unionization are higher - they have a threshold to maintain with a big penalty, so there are only so many people they can fire!

[1] https://en.wikipedia.org/wiki/Gigafactory_New_York#Jobs_comm... [2] https://buffalonews.com/business/local/how-tesla-built-its-b...